This proposed Advanced Center For Interventions And Services Research (PA NUMBER: PAR-01-089),entitled The Center for Prevention and Early Intervention, represents a collaborative effort between the JHU Bloomberg School of Public Health and our community partners in prevention and early intervention (the Baltimore City Public Schools System and the Baltimore Mental Health Systems), and prevention and early intervention researchers at Pennsylvania State University, the University of Alabama, the University of Missouri, the University of Oregon, Columbia University, and Stanford University. The mission of the Center is (1) to improve school-based preventive and early treatment interventions for children and adolescents by bridging epidemiologic, intervention, services, and dissemination and training research through the development of a research structure and research strategies capable of evaluating the effectiveness and sustainability of promising and evidence based interventions; (2) to identify factors that inhibit or facilitate improved prevention and treatment practices and outcomes; (3) to disseminate the knowledge gained in order to improve prevention and treatment research and dissemination and training practices; and (4) to develop within our collaborating community partners the capacity to carry out and disseminate state of the art prevention and early intervention research and evaluations. The Center consists of 3 Cores. The Operations Core provides support to Center collaborators in the following areas: administration, biostatistics, economic analysis, clinical trials, assessment/evaluation, and dissemination and training. The Research Methods Core is focused on advances in biostatistics, economics, and computerized assessment in support of the Center's intervention initiatives. The Principal Research Core provides the structure and support for pilot and feasibility studies aimed at setting the stage for elementary school-based, effectiveness trials of promising and evidence-based prevention and early interventions and assessments. Support over the life of the Center will make it possible: (1) to strengthen and extend research initiatives aimed at evaluating the effectiveness of evidence-based, early preventive and treatment interventions for children and adolescents and (2) to disseminate research on the prevention and treatment of mental disorders in children and adolescents.